Publications (15) View all
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Article: Photoacoustic and optical coherence tomography of epilepsy with high temporal and spatial resolution and dual optical contrasts.
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ABSTRACT: Epilepsy mapping with high spatial and temporal resolution has great significance for both fundamental research on epileptic neurons and the clinical management of epilepsy. In this communication, we demonstrate for the first time in vivo epilepsy mapping with high spatial and temporal resolution and dual optical contrasts in an animal model. Through the variations of a depthresolved optical coherence tomography signal with optical scattering contrast, we observed that epileptic neuron activities modulated the optical refractive index of epileptic neurons and their surrounding tissue. Simultaneously, through neurovasculature coupling mechanisms and optical absorption contrast, we used photoacoustic signals to document the hemodynamic changes of the microvasculature surrounding the epileptic neurons. The epilepsy mapping results were confirmed by a simultaneously recorded electroencephalogram signal during epileptic seizure. Our new epilepsy mapping tool, with high temporal and spatial resolution and dual optical contrasts, may find many applications, such as drug development and epilepsy surgery.Journal of neuroscience methods 04/2013; · 2.30 Impact Factor -
Article: Real-time four-dimensional optical-resolution photoacoustic microscopy with Au nanoparticle-assisted subdiffraction-limit resolution.
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ABSTRACT: Photoacoustic microscopy (PAM) offers label-free, optical absorption contrast. A high-speed, high-resolution PAM system in an inverted microscope configuration with a laser pulse repetition rate of 100,000 Hz and a stationary ultrasonic transducer was built. Four-dimensional in vivo imaging of microcirculation in mouse skin was achieved at 18 three-dimensional volumes per second with repeated two-dimensional (2D) raster scans of 100 by 50 points. The corresponding 2D B-scan (50 A-lines) frame rate was 1800 Hz, and the one-dimensional A-scan rate was 90,000 Hz. The lateral resolution is 0.23 ± 0.03 μm for Au nanowire imaging, which is 2.0 times below the diffraction limit.Optics Letters 04/2011; 36(7):1137-9. · 3.40 Impact Factor -
Article: Fast voice-coil scanning optical-resolution photoacoustic microscopy.
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ABSTRACT: We developed a photoacoustic imaging system that has real-time imaging capability with optical resolution. The imaging system is capable of scanning at 20 Hz over a 9 mm range and up to 40 Hz over a 1 mm scanning range. A focused laser beam provides a lateral resolution of 3.4 μm as measured in an optically nonscattering medium. Flows of micrometer-sized carbon particles or whole blood in a silicone tube and individual red blood cells (RBCs) in mouse ear capillaries were also imaged in real time, demonstrating the capability to image highly dynamic processes in vivo at a micrometer-scale resolution.Optics Letters 01/2011; 36(2):139-41. · 3.40 Impact Factor -
Article: Hybrid-scanning optical-resolution photoacoustic microscopy for in vivo vasculature imaging.
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ABSTRACT: Recently developed optical-resolution photoacoustic microscopy (OR-PAM), which is based on the detection of optical absorption contrast, is complementary to other optical microscopy modalities such as optical confocal microscopy, optical coherence tomography, and multiphoton microscopy. A hybrid optical-mechanical scanning configuration increases the imaging speed of OR-PAM significantly, facilitating many demanding biomedical applications. With a high-pulse-repetition-rate laser, the hybrid-scanning OR-PAM can acquire one-dimensional depth-resolved images (A-lines) at 5 kHz and two-dimensional B-scan images containing 800 A-lines at 6.25 Hz. We demonstrated in vivo in a mouse three-dimensional imaging of the iris vasculature in 128 s for an 800x800x200 data set and of the ear vasculature in 256 s for an 800x1600x200 data set.Optics Letters 05/2010; 35(10):1521-3. · 3.40 Impact Factor -
Article: Three-dimensional optical coherence tomography imaging of retinal sheet implants in live rats.
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ABSTRACT: To obtain three-dimensional images from retinal transplants in live animals and evaluate the placement and structural quality of the transplants. Donor retinal sheets were isolated from E19 fetuses of transgenic rats expressing human alkaline phosphatase (hPAP), and transplanted to the subretinal space of 19-56 days old S334ter-3 rat recipients with fast retinal degeneration (average age at surgery 32 days). A total of 143 rats were imaged 1 day to 2.8 months after surgery, using a Fourier-domain optical coherence tomography (FDOCT) system, with an axial resolution of 3.5 microm. The CCD A-line integration time was set at 200 micros for better visualization of degenerated retina. After targeting the transplant area, 139 or 199 consecutive slices were scanned. Projection images and movies of the retinal transplant area were computed and later compared with histology. OCT scans identified 137 of 141 transplants as a thickening of the degenerated retina. OCT indicated the laminar structure of the transplants and surgical defects, such as RPE/choroid damage with an accuracy rate between 83 and 99%. Three-dimensional projections showed the transplant position in the retina in relation to the optic disc. Histology of transplants by hPAP and hematoxylin-eosin staining was correlated with the OCT results. Optical coherence tomography is an excellent tool to image retinal layers in a live rat. This procedure helps to evaluate the placement and quality of the transplants in the living eye.Journal of neuroscience methods 02/2010; 188(2):250-7. · 2.30 Impact Factor
